Friday, February 14, 2003

Investigators Say Hole in Aluminum Wrecked Shuttle
The panel investigating the loss of the space shuttle Columbia said today that a hole developed in its aluminum skin, allowing superheated gas to flow into the left wing and causing the ship's destruction.

NASA also released a highly detailed map showing for the first time that the Columbia's sensors began detecting subtle signs of trouble when the craft was still above the Pacific Ocean, 400 miles off the coast of Sonoma County in Northern California.

The new map, combined with the board's finding that a hole was burning through spacecraft's skin, suggested that observations of glowing pieces falling away from the shuttle over California carry significant clues to the ultimate cause of the disaster. It could mean that the catastrophic series of failures began almost the moment the Columbia re-entered the atmosphere, lending credence to theories that its exterior had been damaged earlier — perhaps by a piece of foam insulation that fell off during launching, perhaps by space debris or by some other phenomenon like a storm in space.

The statement today from the board about a hole means that engineers have all but eliminated an earlier theory of the disaster: that the aluminum skin was not breached, but that a lost or damaged tile on the skin allowed heat to be conducted into the wheel well in the wing, where sensor failures gave the first indications of trouble.

"Preliminary analysis by a NASA working group this week indicates that the temperature indications seen in Columbia's left wheel well during entry would require the presence of plasma," the superheated gas that surrounds the shuttle as it enters the atmosphere, the board said in a statement released late today.

The board also said that "the heat transfer through the structure, as from a missing tile, would not be sufficient to cause the temperature indications seen in the last minutes of flight." Instead, the panel said, only a jet of plasma, which can reach 3,000 degrees under the brutal conditions of re-entry, could have caused the heating and failures that were detected before the shuttle disintegrated on Feb. 1.

The board did not address the central mystery of how the hole was created. Early suspicions focused on damage from a piece of falling foam insulation that struck the wing about 80 seconds into the launching, and the new finding does not rule out that problem as a possible cause. But since then, other possible sources of damage have also been considered, including collision with space debris or meteoroids.
http://www.nytimes.com/2003/02/14/national/nationalspecial/14SHUT.html?pagewanted=all&position=top

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